At a news conference April 12, House Speaker Paul Ryan (R-Wis.) reiterated that he does not want to be his party's nominee for president, saying, "I should not be considered, period, end of story." (Reuters)

House Speaker Paul D. Ryan (R-Wis.) on Tuesday delivered a forceful statement rejecting calls from establishment Republicans who want him to usurp their party’s presidential nomination from the remaining contestants in that race.

Ryan, who has spent a couple of months making these statements, to no avail, arranged a hastily called afternoon news conference inside the Republican National Committee headquarters, where he insisted — in his clearest terms yet — to the GOP’s big-donor and lobbyist class that he will not attempt to claim the nomination at the July convention in Cleveland.

“Let me be clear. I do not want, nor will I accept, the nomination for our party,” Ryan said.

Civil War general William Tecumseh Sherman often faced calls to run for president after he retired from the military, prompting his most famous declaration that lives on in politics today: “I will not accept if nominated and will not serve if elected.”

Ryan has made the equivalent of such statements about a possible 2016 run many times — in very clear terms. But worried about the possible nomination of Donald Trump or Sen. Ted Cruz (R-Tex.), Washington’s chattering class has largely decided to ignore the speaker’s statements, envisioning the 46-year-old in a head-to-head contest with the Democratic front-runner, Hillary Clinton.

Despite her own low favorability ratings as an elected official, Clinton crushes Trump in early horse-race polling, particularly in key battleground states where a clutch of key Senate and House races could be adversely impacted down-ballot by Trump’s candidacy. Cruz, running second to Trump for the GOP nomination, fares better than the real estate mogul but not by much, and the senator is loathed by a GOP establishment that has openly flouted his candidacy.

With it looking increasingly likely that no GOP candidate will claim the 1,237 delegates required to claim the nomination on the first ballot in Cleveland, some establishment Republicans have conjured dreams of Ryan jumping into the fray on the second, third and fourth ballots, at which point delegates to the Republican National Convention are not bound to vote for the candidate who won their state or district.

These veteran Republican operatives have kept the “Draft Ryan” movement alive despite repeated blunt statements by the speaker that he has no desire to take such a risky move.

House Speaker Paul Ryan (R-Wis.). (J. Scott Applewhite/AP)

As evidence of the emerging Ryan campaign, they’ve latched onto the production of campaign-style videos that have come out of the speaker’s office — although the previous speaker, John A. Boehner (R-Ohio), also issued these same glossy videos produced by the same aide. But Ryan was Mitt Romney’s running mate, and expectations around the Wisconsin Republican are different.

A month ago, after Boehner floated the idea of Ryan running, the current speaker cursed out his predecessor at a private event in Washington. The next day, he reiterated something he has said for many months: that to become president one has to run for president, and he decided last year not to do so.

“It’s not going to be me. It should be somebody running for president,” Ryan told the congressional press corps in mid-March.

On Tuesday, Ryan said that in his role as co-chairman of the convention — usually an honorific title given to the top two congressional caucus leaders — he plans to push a rule that would limit delegates to casting votes on any ballot to those that ran for the nomination in the primary season.

Trump’s campaign welcomed Ryan’s statement.

“We expect Paul Ryan means what he says and there’s not going to be anything for him to run for because we’re going to win on the first ballot,” said Trump senior adviser Paul Manafort. “And he’ll be the beneficiary of that because with us winning on the first ballot, we’ll unite the party and he’ll be able to have a Republican House of Representatives. And he knows that. Why would he want to risk a second or third ballot and the majority of the House? That doesn’t make sense.”

Besides his own unwillingness to run, Ryan would be taking an incredibly high-risk move if he were to acquiesce to the whisper campaign and try to secure the nomination in Cleveland.

Given that roughly 75 percent of Republican primary voters favor Trump or Cruz, both running against the establishment, it’s unclear that the delegates would even agree to nominate Ryan — an establishment favorite, though he has close ties to conservatives, whose career has been marked by mostly risk-averse moves.

Such a move could also prompt staunch conservatives to find a write-in candidate to vote for rather than backing Ryan.

If he were to get the nomination and lose the election to Clinton, Ryan’s tenure as House GOP leader also might come crumbling down, ending a political career that appears to have decades of potential to come.

On Tuesday, Ryan sought to put an end to any of these “will he or won’t he” discussions regarding his willingness to be the party’s nominee this year.

“I should not be considered. Period. End of story,” he said.

But Ryan also said he isn’t going to retreat from his party’s campaign season debate, noting he has an agenda to move as speaker that will include a series of policy proposals the House GOP can present to voters. He noted that when he became speaker last year he promised to improve how the party communicates its message to the public and explained his high-profile role of speeches and campaign-style videos as part of his months-long effort to have the House caucus rally around a bold agenda for the fall campaign.